Field of the Invention
The present invention relates to an endoscope apparatus, and specifically, relates to an endoscope apparatus including an erecting operation member for erecting a forceps elevator (treatment tool elevator) of a distal end part a traction of an operation wire.
Description of the Related Art
In an ultrasonic inspection in an ultrasonic endoscope, tissue sampling and suction by a puncture needle are optionally performed under the ultrasonic endoscope.
Moreover, a guide wire and a contrast tube are inserted in a bile duct or the like in duodenoscopy and endoscopic retrograde cholangiopancreatography (ERCP) is performed.
A puncture needle and a guide wire, and so on, are inserted from a treatment tool entry port of an endoscope and led out from a treatment tool exit port provided in the distal end part of the endoscope through a treatment tool insertion channel.
A forceps elevator is provided in the treatment tool exit port, and the forceps elevator is configured so that it can move from a reclined state to a erected state by operating an erecting operation member and pulling the operation wire (see Japanese Utility Model Publication No. 61-15841). By this means, the puncture needle or the guide wire, which is led out from the treatment tool exit port, becomes able to approach a body wall or a duodenal papilla at a desired angle.
Japanese Utility Model Publication Nos. 61-15841 and 63-2007 disclose that, in a power transmission mechanism that couples an operation wire connected to a forceps elevator with an erecting operation member such that power can be transmitted, a load generating device includes: a friction member which applies a friction force to the movement of an erecting operation member in a direction (reclining side) in which the forceps elevator reclines; and a one-way clutch configured so as not to add a friction force from the friction member to the movement of the erecting operation member in a direction (erecting side) in which the forceps elevator is erected. By this means, the holding force against the restoring force to restore a treatment tool which is bended along the forceps elevator to a straight state is applied to the erecting operation member so that the forceps elevator is not reclined even in a case where an operator releases his/her hands from the erecting operation member, and the friction force from the friction member which is an unnecessary load is not applied when the erecting operation member is operated toward the erecting side.